//
//  LoadingViewController.swift
//  QuickSearchLocation
//
//  Created by Destiny on 2024/12/31.
//

import UIKit
import Photos

class LoadingViewController: UIViewController {
    private let photoClassifier = PhotoClassifier()
    private let progressView = UIProgressView(progressViewStyle: .default)
    private let statusLabel = UILabel()
    private let resultLabel = UILabel()
    private let collectionView: UICollectionView
    private var similarGroups: [[PHAsset]] = []
    private var timer: Timer?
    
    // 添加详细进度标签
    private let detailProgressLabel = UILabel()
    private let percentageLabel = UILabel()
    
    override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) {
        // 初始化 CollectionView
        let layout = UICollectionViewFlowLayout()
        layout.scrollDirection = .vertical
        layout.minimumLineSpacing = 10
        layout.minimumInteritemSpacing = 5
        
        let screenWidth = UIScreen.main.bounds.width
        let width = (screenWidth - 20) / 3
        layout.itemSize = CGSize(width: width, height: width)
        layout.sectionInset = UIEdgeInsets(top: 10, left: 5, bottom: 10, right: 5)
        layout.headerReferenceSize = CGSize(width: screenWidth, height: 40)
        
        collectionView = UICollectionView(frame: .zero, collectionViewLayout: layout)
        
        super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        setupUI()
        startClassifying()
    }
    
    private func setupUI() {
           view.backgroundColor = .white
           
           // 设置进度容器视图
           let progressContainer = UIView()
           progressContainer.translatesAutoresizingMaskIntoConstraints = false
           view.addSubview(progressContainer)
           
           // 配置所有标签
           statusLabel.textAlignment = .center
           statusLabel.font = .systemFont(ofSize: 16, weight: .medium)
           
           detailProgressLabel.textAlignment = .center
           detailProgressLabel.font = .systemFont(ofSize: 14)
           detailProgressLabel.textColor = .darkGray
           
           percentageLabel.textAlignment = .center
           percentageLabel.font = .systemFont(ofSize: 14, weight: .medium)
           percentageLabel.textColor = .systemBlue
           
           resultLabel.textAlignment = .center
           resultLabel.numberOfLines = 0
           resultLabel.font = .systemFont(ofSize: 14)
           
           // 配置进度条
           progressView.progressTintColor = .systemBlue
           progressView.trackTintColor = .systemGray5
           
           // 添加所有视图
           [statusLabel, progressView, detailProgressLabel, percentageLabel, resultLabel].forEach {
               $0.translatesAutoresizingMaskIntoConstraints = false
               progressContainer.addSubview($0)
           }
           
           // 布局约束
           NSLayoutConstraint.activate([
               progressContainer.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor),
               progressContainer.leadingAnchor.constraint(equalTo: view.leadingAnchor),
               progressContainer.trailingAnchor.constraint(equalTo: view.trailingAnchor),
               progressContainer.heightAnchor.constraint(equalToConstant: 180),
               
               statusLabel.topAnchor.constraint(equalTo: progressContainer.topAnchor, constant: 20),
               statusLabel.centerXAnchor.constraint(equalTo: progressContainer.centerXAnchor),
               
               progressView.topAnchor.constraint(equalTo: statusLabel.bottomAnchor, constant: 15),
               progressView.centerXAnchor.constraint(equalTo: progressContainer.centerXAnchor),
               progressView.widthAnchor.constraint(equalTo: progressContainer.widthAnchor, multiplier: 0.8),
               
               detailProgressLabel.topAnchor.constraint(equalTo: progressView.bottomAnchor, constant: 10),
               detailProgressLabel.centerXAnchor.constraint(equalTo: progressContainer.centerXAnchor),
               
               percentageLabel.topAnchor.constraint(equalTo: detailProgressLabel.bottomAnchor, constant: 5),
               percentageLabel.centerXAnchor.constraint(equalTo: progressContainer.centerXAnchor),
               
               resultLabel.topAnchor.constraint(equalTo: percentageLabel.bottomAnchor, constant: 15),
               resultLabel.centerXAnchor.constraint(equalTo: progressContainer.centerXAnchor),
               resultLabel.widthAnchor.constraint(equalTo: progressContainer.widthAnchor, multiplier: 0.8)
           ])
           
           // 设置 CollectionView
           collectionView.backgroundColor = .white
           collectionView.delegate = self
           collectionView.dataSource = self
           collectionView.register(PhotoCell.self, forCellWithReuseIdentifier: "PhotoCell")
           collectionView.register(
               HeaderView.self,
               forSupplementaryViewOfKind: UICollectionView.elementKindSectionHeader,
               withReuseIdentifier: "Header"
           )
           
           collectionView.translatesAutoresizingMaskIntoConstraints = false
           view.addSubview(collectionView)
           
           NSLayoutConstraint.activate([
               collectionView.topAnchor.constraint(equalTo: progressContainer.bottomAnchor),
               collectionView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
               collectionView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
               collectionView.bottomAnchor.constraint(equalTo: view.bottomAnchor)
           ])
       }
    
    private func startClassifying() {
        // 重置UI
        progressView.progress = 0
        statusLabel.text = "正在准备..."
        detailProgressLabel.text = "初始化中"
        percentageLabel.text = "0%"
        resultLabel.text = ""
        
        // 请求相册权限
        PHPhotoLibrary.requestAuthorization { [weak self] status in
            guard let self = self else { return }
            
            DispatchQueue.main.async {
                if status == .authorized {
                    self.beginPhotoClassification()
                } else {
                    self.statusLabel.text = "需要相册访问权限"
                    self.detailProgressLabel.text = "请在设置中允许访问相册"
                }
            }
        }
    }
    
    private func beginPhotoClassification() {
            statusLabel.text = "正在加载照片..."
            
            let fetchOptions = PHFetchOptions()
            let allPhotos = PHAsset.fetchAssets(with: .image, options: fetchOptions)
            
            // 更新总数
            detailProgressLabel.text = "共发现 \(allPhotos.count) 张照片"
            
            photoClassifier.classifyPhotos(
                assets: allPhotos,
                progressHandler: { [weak self] (stage, progress) in
                    DispatchQueue.main.async {
                        self?.updateProgress(stage: stage, progress: progress)
                    }
                },
                completion: { [weak self] result in
                    guard let self = self else { return }
                    
                    DispatchQueue.main.async {
                        self.updateProgress(stage: "分类完成", progress: 1.0)
                        
                        // 更新结果显示
                        var resultText = "分类结果：\n"
                        resultText += "截图：\(result.screenshots.count) 张\n"
                        resultText += "相似照片组：\(result.similarPhotos.count) 组"
                        self.resultLabel.text = resultText
                        
                        // 更新相似照片展示
                        self.similarGroups = result.similarPhotos
                        self.collectionView.reloadData()
                    }
                }
            )
        }
    
    private func updateProgress(stage: String, progress: Float) {
            statusLabel.text = stage
            progressView.progress = progress
            percentageLabel.text = "\(Int(progress * 100))%"
            
            switch stage {
            case "正在加载照片...":
                detailProgressLabel.text = "正在读取照片数据"
            case "正在提取特征...":
                detailProgressLabel.text = "正在分析照片内容"
            case "正在比较相似度...":
                detailProgressLabel.text = "正在查找相似照片"
            case "分类完成":
                detailProgressLabel.text = "处理完成"
            default:
                break
            }
        }
}

// MARK: - UICollectionView DataSource & Delegate
extension LoadingViewController: UICollectionViewDataSource, UICollectionViewDelegate {
    func numberOfSections(in collectionView: UICollectionView) -> Int {
        return similarGroups.count
    }
    
    func collectionView(_ collectionView: UICollectionView,
                       numberOfItemsInSection section: Int) -> Int {
        return similarGroups[section].count
    }
    
    func collectionView(_ collectionView: UICollectionView,
                       cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(
            withReuseIdentifier: "PhotoCell",
            for: indexPath
        ) as! PhotoCell
        
        let asset = similarGroups[indexPath.section][indexPath.item]
        cell.configure(with: asset)
        return cell
    }
    
    func collectionView(_ collectionView: UICollectionView,
                       viewForSupplementaryElementOfKind kind: String,
                       at indexPath: IndexPath) -> UICollectionReusableView {
        if kind == UICollectionView.elementKindSectionHeader {
            let header = collectionView.dequeueReusableSupplementaryView(
                ofKind: kind,
                withReuseIdentifier: "Header",
                for: indexPath
            ) as! HeaderView
            
            let groupCount = similarGroups[indexPath.section].count
            header.titleLabel.text = "相似组 \(indexPath.section + 1) (\(groupCount) 张)"
            return header
        }
        return UICollectionReusableView()
    }
}

// MARK: - PhotoCell
class PhotoCell: UICollectionViewCell {
    private let imageView = UIImageView()
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        setupUI()
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    private func setupUI() {
        imageView.contentMode = .scaleAspectFill
        imageView.clipsToBounds = true
        imageView.translatesAutoresizingMaskIntoConstraints = false
        contentView.addSubview(imageView)
        
        NSLayoutConstraint.activate([
            imageView.topAnchor.constraint(equalTo: contentView.topAnchor),
            imageView.leadingAnchor.constraint(equalTo: contentView.leadingAnchor),
            imageView.trailingAnchor.constraint(equalTo: contentView.trailingAnchor),
            imageView.bottomAnchor.constraint(equalTo: contentView.bottomAnchor)
        ])
    }
    
    func configure(with asset: PHAsset) {
        let options = PHImageRequestOptions()
        options.deliveryMode = .fastFormat
        
        PHImageManager.default().requestImage(
            for: asset,
            targetSize: CGSize(width: 200, height: 200),
            contentMode: .aspectFill,
            options: options
        ) { [weak self] image, _ in
            self?.imageView.image = image
        }
    }
}

// MARK: - HeaderView
class HeaderView: UICollectionReusableView {
    let titleLabel = UILabel()
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        setupUI()
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    private func setupUI() {
        titleLabel.font = .systemFont(ofSize: 16, weight: .medium)
        titleLabel.translatesAutoresizingMaskIntoConstraints = false
        addSubview(titleLabel)
        
        NSLayoutConstraint.activate([
            titleLabel.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 15),
            titleLabel.centerYAnchor.constraint(equalTo: centerYAnchor)
        ])
    }
}